1. Field of the Invention
The present invention relates to a bread packaging system for packaging the bread with a packaging material, in particular, to a bread packaging system comprising a reciprocating motion mechanism that employs an endless revolving member that revolves in a single direction.
2. Description of the Related Art
Bread packaging apparatuses for packaging a long loaf bread (for example, three-loaf length) into a packaging material such as a polyethylene bag have been conventionally used. For example, JP Patent Application Publication No. S63-000021 discloses a conventional bread packaging apparatus comprising a reciprocating motion mechanism that employs a cam and link mechanism. This conventional bread packaging apparatus comprises a scoop that reciprocates a bag stacking unit on which folded polyethylene bags are stacked and a packaging place for wrapping the loaf bread in the bag. The scoop reciprocates between the bag stacking unit and the packaging place in order to hold the packaging material at the bag staking unit and package the loaf bread at the packaging place.
On the other hand, a reciprocating motion mechanism of a bread packaging apparatus disclosed in U.S. Pat. No. 5,743,071 comprises a pair of pulleys spaced apart from each other; and a toothed belt wound around the pair of pulleys. Once the rotation force from a drive motor is transmitted to one of the pulleys, the toothed belt is revolved and thereby the rotation force is transmitted to the other pulley. Further, the loaf bread packaging apparatus comprises a link bar, wherein one end portion of the link bar is connected to the toothed belt and the other end portion of the link bar is connected to the scoop.
The link bar reciprocates in the linear moving area of the toothed belt extending between both pulleys, which allows the scoop to reciprocate. That is, one end portion of the link bar connected to the toothed belt does not pass over both pulleys. Therefore, the drive motor for driving the reciprocating motion mechanism accelerates and decelerates so that the one end portion of the link bar moves from near one pulley toward near the other pulley and, without exceeding that pulley, returns to near the one pulley.
In the reciprocating motion mechanism employing the cam and link as disclosed in JP Patent Application Publication No. S63-000021, not only is the structure complicated, but also the number of link portions of the components becomes great. The larger number of the link portions may cause the noise due to the backlash or looseness at the link portions, which makes it difficult to run the bread packaging apparatus stably for a long term.
Further, the reciprocating motion mechanism as disclosed in U.S. Pat. No. 5,743,071 is configured to reciprocate the link bar linking the scoop with the endless revolving member within the linear moving area between two pulleys by the drive motor. Therefore, it is necessary to abruptly brake the drive motor to reverse the rotation direction when one end portion of the link bar comes to the turning point, and it is necessary to make a rapid acceleration and deceleration when one end portion of the link bar is between the pulleys. As a result, the inertia load applied to the drive motor makes it difficult to ensure the durability of the drive motor.
In addition, it may be possible to use a metal chain as the endless revolving member, however, which tends to increase the noise of the bread packaging apparatus.